The present invention relates to ink jet printers, and more particularly to an ink jet printer for use in printing digital photographic images.
Digital photographic images provide significant advantages over conventional photographic images in that they can be manipulated, stored, retrieved, and transmitted using digital computer and data communication technology. Digital photographic images can be generated either by scanning photographic images captured on conventional photographic film, or directly by digital cameras employing solid state image sensors. Hard copy display prints of digital color photographic images are presently produced using thermal printers, electrographic printers, scanners for exposing conventional silver halide photographic paper, and ink jet printers.
The largest share of consumer photographic images are currently produced using optical printers on photographic paper. It has been realized however that consumer photofinishing would benefit from the advantages of digital image processing, since the digital images can be digitally processed for better correction of color balance and exposure, and can be digitally manipulated to add text or special effects and can be combined with other images. The images captured on silver halide photographic film are scanned to create color digital images, the color digital images are processed to correct color balance and exposure, and then printed using a color digital printer. Presently, the only digital printers for consumer photofinishing that are available on the market are of the type that use a scanning light beam to expose conventional silver halide photographic paper. Such digital printers still use wet chemical processing to develop the exposed photographic paper. Handling and disposal of the photo processing chemicals is costly and takes up space, which also must be paid for, for example in the form of rent. There is a need therefore for a digital photofinishing printer that avoids the problems and costs associated with wet chemical photographic paper processing.
Of the competing technologies, thermal printing, electrography and ink jet printing; thermal printing is limited by printing speed and cost of materials, and electrography is limited by equipment cost and complexity. It appears therefore that ink jet printing technology may be the best candidate to offer an improvement over scanned silver halide printers for digital consumer photofinishing.
It is well known to employ ink jet printers to produce hard copy prints of digital photographic images. Lower resolution images are produced on desk top ink jet color printers having resolution in the range of 300 to 1200 dpi. Large format color images are produced using graphic arts ink jet printers, see for example, published European Patent Application EP 0 710 561 A2, published Aug. 5, 1996, entitled Printer and Ink Cartridge to be Employed in Same, by Ikkatai; and published PCT application WO 97/28003, published Aug. 7, 1997, entitled Heated Inkjet Print Media Support System, by Rasmussen et al. Although high resolution color ink jet printing is likely to become a preferred mode for photofinishing, existing ink jet printers are severely limited by their speed of throughput. There is a need therefore for a high throughput, high resolution ink jet printer for photofinishing.
An ink jet printer for making photographic prints includes at least one paper supply for holding a supply of print paper and a sheet paper transport belt arranged to receive sheets of print paper from the paper supply and transport the sheets through the printer. A back printer is located between the paper supply and the paper transport belt for applying back prints to the print paper. A full print width color ink jet print head is located over a first portion of the transport belt for printing an image on a paper sheet. A paper support located under the ink jet print head is provided with ink overspill collection grooves to collect overspilled ink from the ink jet print head. An image sensor located in front of the ink jet print head detects the leading edge of the paper sheet being transported under the print head and a controller connected to the image controls the print head to print an image that is slightly wider and shorter than the paper, thereby preventing overspill printing on the leading and trailing edges of the sheet, while allowing slight overspill printing on the sides of the sheet into the overspill collection grooves. A paper dryer is located over a second portion of the vacuum belt transport, the paper dryer includes a source of flowing air for drying the image on the paper. A sheet trimming station is located at the end of the vacuum belt sheet transport for trimming the leading and trailing edges of a sheet after drying.
The ink jet printer according to the present invention has the following advantages. Shrinkage of the printing paper in the drying section has no influence on the print area. Perfect borderless prints can be produced. The printing rate is compatible with the needs of commercial photofinishing operations.